The U.S. Department of Energy (DOE) Office of Enforcement and Oversight (Independent Oversight), within the Office of Health, Safety and Security (HSS), initiated a DOE complex-wide review of emergency preparedness for severe natural phenomena events. This review focused on processes for identifying emergency response capabilities and maintaining a state of readiness in case of a severe natural phenomena event. Reviews were completed at four DOE/National Nuclear Security Administrations sites in 2013.